net.sf.saxon.expr.sort

## Class DocumentSorter

- java.lang.Object
- - net.sf.saxon.expr.Expression
  - - net.sf.saxon.expr.UnaryExpression
    - - net.sf.saxon.expr.sort.DocumentSorter

- All Implemented Interfaces:
    Serializable, SourceLocator, LocationProvider, SaxonLocator, InstructionInfo, Locator

      public class DocumentSorter
      extends UnaryExpression

  A DocumentSorter is an expression that sorts a sequence of nodes into document order.
  See Also:
    Serialized Form

- - ### Field Summary

    - ### Fields inherited from class net.sf.saxon.expr.UnaryExpression

      `operand`

    - ### Fields inherited from class net.sf.saxon.expr.Expression

      `EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, INHERITED_CONTEXT, INSPECTION_CONTEXT, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, NAVIGATION_CONTEXT, NODE_VALUE_CONTEXT, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, W3C_CONSUMING, W3C_FREE_RANGING, W3C_GROUP_CONSUMING, W3C_MOTIONLESS, WATCH_METHOD`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `DocumentSorter(Expression base)`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `int` | `computeSpecialProperties()` Get the static properties of this expression (other than its type).
    `Expression` | `copy()` Copy an expression.
    `boolean` | `effectiveBooleanValue(XPathContext context)` Get the effective boolean value of the expression.
    `void` | `explain(ExpressionPresenter out)` Diagnostic print of expression structure.
    `ItemOrderComparer` | `getComparer()`
    `ExpressionCompiler` | `getExpressionCompiler()` Return the compiler of the DocumentSorter expression
    `String` | `getExpressionName()` Get a name identifying the kind of expression, in terms meaningful to a user.
    `SequenceIterator` | `iterate(XPathContext context)` Return an Iterator to iterate over the values of a sequence.
    `Expression` | `optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType)` Perform optimisation of an expression and its subexpressions.
    `Expression` | `promote(PromotionOffer offer, Expression parent)` Promote this expression if possible
    `Expression` | `simplify(ExpressionVisitor visitor)` Simplify an expression
    `Pattern` | `toPattern(Configuration config, boolean is30)` Convert this expression to an equivalent XSLT pattern
    `Pattern` | `toStreamingPattern(Configuration config, List<String> reasonForFailure)` Convert this expression to a streaming pattern (a pattern used internally to match nodes during push processing of an event stream)

    - ### Methods inherited from class net.sf.saxon.expr.UnaryExpression

      `computeCardinality, displayOperator, equals, getBaseExpression, getItemType, hashCode, iterateSubExpressions, replaceSubExpression, toString, typeCheck`

    - ### Methods inherited from class net.sf.saxon.expr.Expression

      `addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, getImplementationMethod, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getStreamability, getStreamingAdjunct, getSystemId, getSystemId, hasVariableBinding, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterateEvents, iterateSubExpressionInfo, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError`

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

- - ### Constructor Detail

    - #### DocumentSorter

          public DocumentSorter(Expression base)

  - ### Method Detail

    - #### getExpressionName

          public String getExpressionName()

      Get a name identifying the kind of expression, in terms meaningful to a user.
      Overrides:
        `getExpressionName` in class `Expression`
      Returns:
        a name identifying the kind of expression, in terms meaningful to a user. The name will always be in the form of a lexical XML QName, and should match the name used in explain() output displaying the expression.

    - #### getComparer

          public ItemOrderComparer getComparer()

    - #### simplify

          public Expression simplify(ExpressionVisitor visitor)
                              throws XPathException

      Description copied from class: `UnaryExpression`
      Simplify an expression
      Overrides:
        `simplify` in class `UnaryExpression`
      Parameters:
        `visitor` - an expression visitor
      Returns:
        the simplified expression
      Throws:
        `XPathException` - if an error is discovered during expression rewriting

    - #### optimize

          public Expression optimize(ExpressionVisitor visitor,
                            ExpressionVisitor.ContextItemType contextItemType)
                              throws XPathException

      Description copied from class: `UnaryExpression`
      Perform optimisation of an expression and its subexpressions.

      This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.

      Overrides:
        `optimize` in class `UnaryExpression`
      Parameters:
        `visitor` - an expression visitor
        `contextItemType` - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to `Type.ITEM_TYPE`
      Returns:
        the original expression, rewritten if appropriate to optimize execution
      Throws:
        `XPathException` - if an error is discovered during this phase (typically a type error)

    - #### computeSpecialProperties

          public int computeSpecialProperties()

      Description copied from class: `UnaryExpression`
      Get the static properties of this expression (other than its type). The result is bit-signficant. These properties are used for optimizations. In general, if property bit is set, it is true, but if it is unset, the value is unknown.
      Overrides:
        `computeSpecialProperties` in class `UnaryExpression`
      Returns:
        the special properties, as a bit-significant integer

    - #### copy

          public Expression copy()

      Copy an expression. This makes a deep copy.
      Specified by:
        `copy` in class `Expression`
      Returns:
        the copy of the original expression

    - #### promote

          public Expression promote(PromotionOffer offer,
                           Expression parent)
                             throws XPathException

      Promote this expression if possible
      Overrides:
        `promote` in class `UnaryExpression`
      Parameters:
        `offer` - details of the offer, for example the offer to move expressions that don't depend on the context to an outer level in the containing expression
        `parent` - the containing expression in the expression tree
      Returns:
        if the offer is not accepted, return this expression unchanged. Otherwise return the result of rewriting the expression to promote this subexpression
      Throws:
        `XPathException` - if any error is detected

    - #### toPattern

          public Pattern toPattern(Configuration config,
                          boolean is30)
                            throws XPathException

      Convert this expression to an equivalent XSLT pattern
      Overrides:
        `toPattern` in class `Expression`
      Parameters:
        `config` - the Saxon configuration
        `is30` - true if this is XSLT 3.0
      Returns:
        the equivalent pattern
      Throws:
        `XPathException` - if conversion is not possible

    - #### toStreamingPattern

          public Pattern toStreamingPattern(Configuration config,
                                   List<String> reasonForFailure)

      Convert this expression to a streaming pattern (a pattern used internally to match nodes during push processing of an event stream)
      Overrides:
        `toStreamingPattern` in class `Expression`
      Parameters:
        `config` - the Saxon configuration
        `reasonForFailure` - a list which will be populated with messages giving reasons why the expression cannot be converted
      Returns:
        the equivalent pattern if conversion succeeds; otherwise null

    - #### iterate

          public SequenceIterator iterate(XPathContext context)
                                   throws XPathException

      Description copied from class: `Expression`
      Return an Iterator to iterate over the values of a sequence. The value of every expression can be regarded as a sequence, so this method is supported for all expressions. This default implementation handles iteration for expressions that return singleton values: for non-singleton expressions, the subclass must provide its own implementation.
      Overrides:
        `iterate` in class `Expression`
      Parameters:
        `context` - supplies the context for evaluation
      Returns:
        a SequenceIterator that can be used to iterate over the result of the expression
      Throws:
        `XPathException` - if any dynamic error occurs evaluating the expression

    - #### effectiveBooleanValue

          public boolean effectiveBooleanValue(XPathContext context)
                                        throws XPathException

      Description copied from class: `Expression`
      Get the effective boolean value of the expression. This returns false if the value is the empty sequence, a zero-length string, a number equal to zero, or the boolean false. Otherwise it returns true.
      Overrides:
        `effectiveBooleanValue` in class `Expression`
      Parameters:
        `context` - The context in which the expression is to be evaluated
      Returns:
        the effective boolean value
      Throws:
        `XPathException` - if any dynamic error occurs evaluating the expression

    - #### getExpressionCompiler

          public ExpressionCompiler getExpressionCompiler()

      Return the compiler of the DocumentSorter expression
      Overrides:
        `getExpressionCompiler` in class `Expression`
      Returns:
        the relevant ExpressionCompiler

    - #### explain

          public void explain(ExpressionPresenter out)

      Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
      Overrides:
        `explain` in class `UnaryExpression`
      Parameters:
        `out` - the expression presenter used to display the structure

Copyright (c) 2004-2013 Saxonica Limited. All rights reserved.